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PTFE covered wire - how to strip off the PTFE?

N

N_Cook

Jan 1, 1970
0
For high temp applications. The type I have has 2 parts to the PTFE
insulation. The outer strips off easily with any old wire stripper, but
however new , gap limited cutters , will not cut the underlying PTFE.
Outer is double spiral wound PTFE sheet/ribbon I think, heated to lock
together to a certain extent. The inner is more fibrous in nature. Cutting
the remaining inner material , even difficult with a razor. The only
technique I've found, is remove the outer as normal , then .5mm grinding
disc in a Dremmel , only just touching, run all around and then pull off,
rarely cuts a wire strand . Other than some mega-buck NASA/Mil approved
cutter any other ideas?
 
S

Smitty Two

Jan 1, 1970
0
N_Cook said:
For high temp applications. The type I have has 2 parts to the PTFE
insulation. The outer strips off easily with any old wire stripper, but
however new , gap limited cutters , will not cut the underlying PTFE.
Outer is double spiral wound PTFE sheet/ribbon I think, heated to lock
together to a certain extent. The inner is more fibrous in nature. Cutting
the remaining inner material , even difficult with a razor. The only
technique I've found, is remove the outer as normal , then .5mm grinding
disc in a Dremmel , only just touching, run all around and then pull off,
rarely cuts a wire strand . Other than some mega-buck NASA/Mil approved
cutter any other ideas?

The type of stripper shown here:

<http://rocky.digikey.com/weblib/OK International/Web Photo/ST-500.jp
g>

is pretty good with teflon. Sold under various brand names, and also in
different adjustable gauge ranges or in fixed sizes.

For teflon, squeeze fully to cut through insulation, then back off very
slightly to pull off slug.
 
J

Jeffrey Angus

Jan 1, 1970
0
[Using a fume evacuator, or at least a small fan, is a good idea in this
case, to avoid the risk of inhaling the fumes... a nasty respiratory
syndrome can result. Don't do this at all if you keep pet birds
around... they're acutely sensitive to the fumes from overheated
Teflon and etc.]

And nerve damage...

Both nasty side effects.

Good ventilation is a must.

Jeff
 
N

N_Cook

Jan 1, 1970
0
Smitty Two said:
The type of stripper shown here:

<http://rocky.digikey.com/weblib/OK International/Web Photo/ST-500.jp
g>

is pretty good with teflon. Sold under various brand names, and also in
different adjustable gauge ranges or in fixed sizes.

For teflon, squeeze fully to cut through insulation, then back off very
slightly to pull off slug.

Thats the type I use.
I think I'll make my own cutter, a pair of razor blades set with a tapered
gap between cutting edges (gap a bit larger than ext diam down to wire
diam). Push the wire down the gap in 2 orthogonal directions and then rotate
round at the narrow end. Then sleeve should slide off easily as its the
cutting completely around that is the problem. I'd rather avoid melting of
PTFE (the fluoro bit) especially as it cuts so easily.
Hopefully something like a minimal version of these PTFE specific cutters,
I only have one drum of one size of this wire, so no adjuster needed

http://int.rsdelivers.com/product/rs/o6804/ptfe-wire-stripper-091-45mmdia-cu
tting/0608301.aspx
http://docs-europe.electrocomponents.com/webdocs/001b/0900766b8001b254.pdf
 
N

N_Cook

Jan 1, 1970
0
Works a treat, cutting this pesky thin inner layer of PTFE and not the wire
filaments.

Two 2inch lengths of 12mm diameter hotmelt sticks. Temp controlled solder
iron , melt a slot axially in one. With a pair of razor blades gripped in an
engineer's cramp with gap one end , wider than the outer PTFE, and the other
with blade edges touching at a point. Push the wide gap end into the
hotmelt. Cool and repeat with the other end. Mark along the razor edge where
the stripped wire falls to.
Push some of the sleeved wire down to just beyond this point and drop
hotmelt , filling the space down to the closed gap end.
One sliding cut and 180 degree rotation is all that is needed , slide away,
remove from the slot and pull off the cut sleeving.
 
S

Smitty Two

Jan 1, 1970
0
N_Cook said:
Thats the type I use.
I think I'll make my own cutter, a pair of razor blades set with a tapered
gap between cutting edges (gap a bit larger than ext diam down to wire
diam). Push the wire down the gap in 2 orthogonal directions and then rotate
round at the narrow end. Then sleeve should slide off easily as its the
cutting completely around that is the problem. I'd rather avoid melting of
PTFE (the fluoro bit) especially as it cuts so easily.
Hopefully something like a minimal version of these PTFE specific cutters,
I only have one drum of one size of this wire, so no adjuster needed

http://int.rsdelivers.com/product/rs/o6804/ptfe-wire-stripper-091-45mmdia-cu
tting/0608301.aspx
http://docs-europe.electrocomponents.com/webdocs/001b/0900766b8001b254.pdf

Glad your home-made gadget worked, but the cutters I referenced are the
ones we use every day for stripping teflon. I'm surprised they wouldn't
do it for you. It does take a bit of technique as noted, setting depth
to cut fully through, then backing off pressure to remove slug. The 90
degree rotate and 2nd cut helps, but for production work is too slow.
 
N

N_Cook

Jan 1, 1970
0
Smitty Two said:
http://docs-europe.electrocomponents.com/webdocs/001b/0900766b8001b254.pdf

Glad your home-made gadget worked, but the cutters I referenced are the
ones we use every day for stripping teflon. I'm surprised they wouldn't
do it for you. It does take a bit of technique as noted, setting depth
to cut fully through, then backing off pressure to remove slug. The 90
degree rotate and 2nd cut helps, but for production work is too slow.


This wire is very fine filament multistrand. perhaps 30 wire strands. If it
was solid conductor it would be easier to strip. But the main problem is the
multiple thin sleeve layers , perhaps 3, under the thick outer sleeving.
PTFE seems to be strong in one sense and transverse very weak. If the fibrey
part was laid up transversely it would easily part at the cutting point, but
the layup is strong axially.
 

shrtrnd

Jan 15, 2010
3,876
Joined
Jan 15, 2010
Messages
3,876
It may seem like a pain, but I use an Exacto-knife. Make a complete cut, all the way around the wire. It's the only thing I've found that works consistently.
I have one of the hand-held multi-sized wire strippers (Ideal Stripmaster). If you have a LOT of stripping to do, I'd consider one. Word of warning. The cheap model ($50 US), is for regular wire. You need the more expensive cutting dies MADE for stripping teflon coated wire. They work good, but'll run you closer to $100 US.
 
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